This invention relates to the generation of energy from a moving fluid.
A number of systems have been proposed for extracting energy from waves. Reference is made in this respect to US2011/0101696; US2012/0038163 and U.S. Pat. No. 4,271,668. The last-mentioned case discloses a counter-rotating turbine which converts energy from an alternating air flow above a water surface into mechanical energy. In US2012/0038163 use is made of a dual rotor turbine configuration responsive to bidirectional air flow. US2011/0101696 makes use of an air turbine which rotates in one direction for an incident air flow received from opposite directions.
Oscillating water column devices for converting wave energy into usable electrical or mechanical energy are normally on shore, near shore or off shore, units which are rigidly erected on the ocean floor or which are tethered in a rigid manner to the ocean floor. During storm conditions these devices are vulnerable to damage and destruction.
The present invention is concerned with apparatus of simplified construction which can generate energy from fluid which flows alternately in opposite directions, and which has an enhanced capability to withstand the effects of stormy conditions.